What should i do to make my fisher mama bear or grandpa bear more efficient?

yetty734 Posted By yetty734, May 11, 2008 at 7:55 PM

  1. yetty734

    yetty734
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    Dec 10, 2007
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    I have either a fisher mama bear or granpa bear woodburning stove with no baffle, secondary combustion or anything. What can i do for a reasonable small amount of money to improve its efficiency. I would imagine that installing a baffle would be my number one thing to do, but how do i go about doing this.

    does anyone know if 5-6 cords sounds alright for heating 2000 square feet from a basement in a 45 year old house with this stove?

    im thinking its a mama bear stove because dont all granpabear stoves have a baffle?

    thanks for the advise

    cody
     
  2. Todd

    Todd
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    It may be better to just sell the stove this fall and purchase a new EPA stove. A new stove will end up paying for itself in a few years or less.

    But if I was to modify a Fisher, I would weld some brackets and insert a ceramic baffle in the back of the firebox. You want the air to create an "S" pattern in the firebox to keep the gas and smoke in the firebox longer so it will burn.

    I'm going to install a baffle into my masonry heatform fireplace this fall and see if I can get some secondary combustion and a cleaner burn. I already installed air tight glass doors and outside combustion air, just need a baffle and some way to control the combuston air.
     
  3. begreen

    begreen
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    I agree. Considering that it can be replaced with a stove for under $700 that will run circles around it for efficiency, it's time for an upgrade. You'll save wood and burn a lot cleaner.

    But if you like tinkering and want to try to make it burn better and know how to weld, it would be a decent project. You'd need to drill aligning holes in both sides and weld in some 1/2" black iron pipes that have holes pre-drilled in them to create a secondary manifold. The pipes would be capped on one side and teed together on the other side ending in a nipple with a gate valve. A baffle would then rest on these pipes. With adjustment of the gate valve you might achieve decent secondary burn after some trial and error. It won't look too pretty, but might work.
     
  4. Redox

    Redox
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    Agreed on all counts. I think back on how fast our old Fisher could go through wood and shudder. World of difference with the new equipment. Besides, the entertainment value of watching that secondary burn is priceless.

    Chris
     
  5. Jags

    Jags
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    To reply to your wood use question: Burning 5 to 6 cords per year to entirely heat your house does not sound unreasonable, BUT you would probably find your wood usage going down to about 4 (maybe a little less) with an EPA cert. stove. Yeah, it is possible to get a relatively clean burn from a pre-epa, but really, its much easier to do with an EPA stove and over a wider heat output range for the stove (read: you can tune an epa stove down and still burn clean).

    As far as mods for this stove, I think BG hit it on the head.
     
  6. Dave_1

    Dave_1
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    Hi Cody,

    try this link

    http://www.hearth.com/econtent/index.php/forums/viewthread/2522/P15/
     
  7. WES999

    WES999
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    Well here is what I did. After reading about the new stoves with secondary burn technology, I decided it would be an interesting project to upgrade my Fisher stove.
    I looked at many of the online stove manuals and looked at the stoves on display at Home Depot and Lowes. I came up with a design for a baffle and secondary air tubes that could be installed with minimal modification to the stove. I modeled the stove and baffle in Pro-E CAD. The baffle is made out of ¼” steel plate, ( it’s made in two pieces so in can fit in the door) , with square tubing attached for the secondary air passage, the air tubes are stainless steel with holes drilled in them. I placed some ceramic insulation on top of the baffle.

    The modifications made quite an improvement, the stove seems to put out much more heat than before, wood consumption is reduced and after 10 or 10 minutes there generally there is no visible smoke from the chimney.
     

    Attached Files:

  8. BrotherBart

    BrotherBart
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    Where is air fed to the secondary manifolds?
     
  9. yetty734

    yetty734
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    that looks pretty good wes. any way you can give me a better set of plans. about how much did that cost you?
     
  10. WES999

    WES999
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    The secondary air enters the stove through a two 5/8” holes in the back of the stove (see the pic). You can also see the cover plates that can close off the secondary air incase of over firing. (I never had to use them). The air holes and the cover plate holes were the only modifications needed to install the baffle and air tube.

    I purchased the stainless steel tubing, rectangular tubing and the ceramic insulation, the plate for the baffle I had. I was able to do all the fab work myself (there is a machine shop at work). I don’t remember the exact cost, probably around $100 of so.

    You should be able to get the general idea from the pics; I could probably E-mail some PDF’s if you need more detail. Be aware that the baffle would have to be sized for your stove as it needs to be somewhat of a snug fit.
     

    Attached Files:

  11. begreen

    begreen
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    nice job wes999.
     
  12. Jimbob

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    Looks good! :)
     
  13. bingles

    bingles
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    Hello wes999, After doing a bunch of looking on web I found these pictures of your fisher mod, is there anyway you can send me more info on what you did. This is exactly what I want to do.

    Thanks a bunch...
    MillwrightBrian
     
  14. pen

    pen
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    Here is another thread you may be interested in.

    This is what I did w/ my old fisher a few years back http://www.hearth.com/econtent/index.php/forums/viewthread/31420/

    There is discussion later about adding secondary burn tubes but I decided not to do it. If the stove had a glass door I would have tried it but didn't like the idea of flying blind.

    Here's a pic

    [​IMG]

    pen
     
  15. sesmith

    sesmith
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    Here's a link to a post I put on the other forum a couple of years ago when I added secondary burn tubes to my stove.

    http://www.arboristsite.com/firewood-heating-wood-burning-equipment/86675.htm

    Not as nice a job as WES999 did on his, but it gets the job done. My stove already had a smoke shelf in it, though. I'm currently working on a cat add-on for it to hopefully squeeze a little more heat out of it and clean it up even more,
     
  16. bingles

    bingles
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    Wow i really like that! I might try that.. too bad my fisher dont have a glass door. I have already made a heat shelf when I moved the exhaust from back of stove to the top. I am getting really good heat just not long enough burn times and kinda mess burns.

    Thanks for sharing those pictures... Guess I am off to the local parts store now.. :)

    Millwrightbrian
     
  17. tntman3210

    tntman3210
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    I have a homemade stove built on the design of the Fischer. You may not want to but I drilled a hole in the middle of the door of my stove for a peep hole. It lets you see the flame and the extra air up high aids in secondary burn. I made a way to close the hole but never do.
     
  18. coaly

    coaly
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    The first post here will explain what stove you have;
    http://www.hearth.com/econtent/index.php/forums/viewthread/53332/
    The rest of the thread should answer any other questions. ( A Papa Bear or Grandpa is needed to heat 2000 sf or more)

    Baffle plates started later as the airtight stove caught on and was smoking up Oregon state. After 1980 most had baffles to reduce smoke. All this info with output particulate is given in the same thread above.

    Here's a thread with a simple baffle with instructions for a Mama Bear. Possibly the easiest and quickest upgrade you can do;
    http://www.hearth.com/econtent/index.php/forums/viewthread/82318/
     
  19. CamFan

    CamFan
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    going back to the original question about burning 5-6 cords of wood how can it be more efficent? shut the draft caps, that is simple. More air means more wood consumed. It is to easy to burn the fishers fast with the ease of letting air into the fire box. to much air in and the heat goes with it. Now if the baffle systems shown and by the way they look great, if they keep the heat in people will let less air to the stove so it is not so hot in the house, less air less wood.. That is where the new stoves have made great strides in efficentcy, less air to the firebox and clean burn, and less wood burned. Now I built fishers, and sold them. I burned them for 25 years maybe longer. The first EPA stove i burned was not an easy chore, I had to teach myself a new method of burning with wood. Burning with a Fisher once you start the fire If you start shuting the draft caps before it gets to hot and I used to always shut the caps and open them back about a 1/2 turn. I did save alot of wood and got the heat i needed. You have to open them about twice a day to keep the firebox and chimney clean. Dealing with people for years while installing and selling fishers I found a majority of them would run their stoves with draft caps half way closed. they got alot of heat but burned alot of wood. Good luck
     
  20. coaly

    coaly
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    Yikes, half way closed is the same as half way open !! My Mama would drive me out and eat wood ! I'm heating 1800 sf. and opening the draft caps a half turn on 32* nights, a little more as it gets colder. Always a fire left in the morning, and yes, open them up a few turns to bring the stack up to temp before idling back down. We cook on ours almost every night, so that hot burn cleans things up. I've found a creosote issue is the wood, not the stove. So adjust accordingly.
     

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